# Colour in Production: Lab Dips, Pantone TCX and Getting Bulk to Match | SSL Newsroom > Source: https://surajmal.com/blog/2026/07/colour-management-lab-dips-guide [SSL Newsroom](/blog) Supply Chain # Colour in Production: Lab Dips, Pantone TCX and Getting Bulk to Match Kolkata · 23 JULY 2026 ·By Surajmal Editorial Team·7 min read Published 23 July 2026 Colour is where a buyer's eye and a mill's chemistry have to agree, and they often disagree for weeks. A shade that looks perfect on a screen is not a target a dyehouse can hit, because a monitor emits light and a dyed fabric reflects it. Getting from an approved colour to a bulk order that actually matches it is one of the slowest, most iterative parts of production, and it sits squarely on the [critical path for fabric](/blog/2026/05/fabric-lead-time-reality): a colour that will not approve holds up dyeing, which holds up cutting. Most of that delay is set at the start, in how colour is briefed, rather than in the dyeing itself. This piece walks the colour approval chain a buyer will meet, from the standard through lab dips to bulk, then sets out how to brief colour so it approves in fewer rounds. ## Start with a physical standard, not a screen colour Colour approval begins with the standard: the reference the dyed fabric will be judged against. The most useful thing a buyer can do is make that standard a physical object, not an image. The common language for this is Pantone's textile system. A **TCX** reference is a cotton swatch dyed to a numbered shade; a **TPG** reference is the same number printed on paper. Both name the colour precisely, so a buyer and a mill in different countries are talking about the same target. A dyed cotton TCX chip is the stronger reference, because it is a physical, textile-surface colour that behaves under light much as the bulk fabric will. A printed paper reference or an on-screen value is a fine starting point, but not a safe final target: paper and cloth reflect light differently, and a screen does not reflect at all. Where a brand owns a colour, the best standard of all is its own dyed swatch of the actual base fabric, held as the master, which removes the guesswork of translating a paper number onto a particular cloth. Whatever the source, the rule holds: approve against something you can hold, in the fibre you are buying. ## The lab dip, and why it takes a few rounds A lab dip is a small trial dyeing, a strike-off on the actual bulk fabric, that the mill sends for approval before committing the full lot. The buyer assesses it against the standard, approves or comments, and the mill adjusts and resubmits. Two to four rounds is normal, and the iteration is not incompetence: it is how a recipe is tuned. Several things make it iterative. The same recipe gives a different result on a different fibre or blend, and dye behaves differently at bulk concentrations than in a beaker. The target itself is a physical match, not a formula, so the dyer is closing a visual gap by trial and correction. A buyer who briefs the shade well, as below, gets there in two rounds instead of four. Lab dips sit inside the wider [sampling sequence](/blog/2026/05/garment-sampling-process), and a late colour approval delays everything downstream. ## How a match is actually assessed A match is judged two ways, visually and instrumentally, and a careful buyer uses both. Visual assessment has to happen under a controlled light source, because colour changes with the light falling on it. Mills and buyers use a **light booth** with standard illuminants, most commonly **D65** (a daylight standard) as the primary, plus a store or incandescent light. Standard and submission are viewed side by side, and the assessor grades how close they are and which way any difference runs (redder, greener, darker). Instrumental assessment uses a **spectrophotometer**, which reads the colour numerically and reports the difference between standard and sample as **Delta-E**: a single number for how far apart two colours are, where smaller is closer. A buyer sets a Delta-E tolerance, a maximum acceptable difference, so approval is not purely one person's eye on one day. **Grey scale** ratings, the same 1-to-5 scale used in [fabric testing](/blog/2026/07/fabric-testing-mill-test-report-guide), grade colour change and staining. The number gives a repeatable measure; the booth catches what a reading can miss, chief among it metamerism. ## Metamerism: a match under one light that fails under another Metamerism is when two colours match under one light source and visibly differ under another. It happens because the standard and the sample were dyed with different colourants, so they reflect light in different patterns that only look identical under one illuminant. Move them from daylight to a shop's warm lighting and the match falls apart. This matters because the garment will be judged in retail lighting, not in a lab, and two matching components, a body and a trim, can drift apart under store light. The defence is to assess under more than one illuminant and reject a metameric pair even when it passes under the primary. ## Bulk: shade bands and lot-to-lot continuity Approving one lab dip is not the end, because bulk fabric is dyed in batches and no two are exactly identical. Two things keep this under control. The first is a **shade band**: a set of samples showing the acceptable range around the standard, typically the standard plus the lightest and darkest ends that still pass. It tells the dyehouse and the inspector how much variation is acceptable, so the call is not remade from scratch on every roll. The second is **shade banding of the bulk itself**, sorting the finished rolls into groups that match closely enough to be cut together, so a garment is never assembled from a slightly dark front and a slightly light sleeve. It also drives **lot-to-lot continuity**: a second delivery, or a reorder next season, should still sit inside the same band, so the customer never sees two versions of the same colour. ## Colourfastness: the colour also has to stay put A colour that matches on day one is only half the job; it has to survive use. This is colourfastness, tested separately: fastness to **washing**, to **light**, to **crocking** (rubbing, dry and wet), and to **perspiration**, among others. These carry their own grey-scale ratings in the [mill test report](/blog/2026/07/fabric-testing-mill-test-report-guide), and they constrain the shade, because deep and bright colours are harder to fix fast. Treat the matched shade and its fastness as one approval, not two, so hitting the colour does not come at the cost of a dye that bleeds in the first wash. ## Briefing colour so it approves faster Most colour delay is set before the first lab dip. A few habits cut the round count. - **Send a physical standard.** A dyed TCX chip, or better a brand-owned dyed swatch, beats a Pantone number in an email and a screen colour outright. Fix it early, in [the first sampling conversation](/blog/2026/03/first-sampling-conversation), so the mill aims at the right target from round one. - **State the light source.** Name the illuminant the colour will be approved under, D65 as primary and any store light that matters, so the mill assesses as you will. - **Set a realistic tolerance.** Give a Delta-E limit and shade band sized to the shade and end use. An over-tight tolerance on a deep colour buys extra rounds for a difference no customer would see. - **Specify the base fabric.** Approve the shade on the actual bulk cloth and its final [weight and construction](/blog/2026/06/fabric-gsm-weight-guide-apparel-buyers), because the same recipe reads differently on another fibre or gsm. - **Approve promptly.** A lab dip waiting a week for comments is a week on the critical path. Fast, clear feedback is the cheapest acceleration you have. ## A short buyer checklist - Standard is a physical, dyed reference in the fibre you are buying, not a screen or paper colour alone. - Approval light source is named (D65 plus any store light), with booth assessment under more than one illuminant. - Delta-E tolerance and shade band are set, sized to the shade and end use. - Lab dip is approved on the actual bulk base fabric, two to four rounds expected. - Metamerism is checked across illuminants, and a metameric pair rejected. - Bulk is shade-banded for lot-to-lot continuity, reorders held to the same band. - Colourfastness (wash, light, crocking, perspiration) is approved alongside the shade, not after it. Colour is not slow because dyehouses are careless; it is slow when the target is vague. Fix a physical standard, define the light and the tolerance, answer lab dips quickly, and colour stops being the step that quietly eats a fortnight off the schedule. 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Every article is reviewed by practitioners who source, sample, and ship the products they write about. On this page - [Start with a physical standard, not a screen colour](#start-with-a-physical-standard-not-a-screen-colour) - [The lab dip, and why it takes a few rounds](#the-lab-dip-and-why-it-takes-a-few-rounds) - [How a match is actually assessed](#how-a-match-is-actually-assessed) - [Metamerism: a match under one light that fails under another](#metamerism-a-match-under-one-light-that-fails-under-another) - [Bulk: shade bands and lot-to-lot continuity](#bulk-shade-bands-and-lot-to-lot-continuity) - [Colourfastness: the colour also has to stay put](#colourfastness-the-colour-also-has-to-stay-put) - [Briefing colour so it approves faster](#briefing-colour-so-it-approves-faster) - [A short buyer checklist](#a-short-buyer-checklist) More from the newsroom - [Supply Chain · 7 min Trims and Components: The Small Parts That Delay Big Orders](/blog/2026/07/trims-components-sourcing-guide) - [Supply Chain · 11 min Fabric Testing: What a Mill Test Report Actually Tells You](/blog/2026/07/fabric-testing-mill-test-report-guide) - [Supply Chain · 9 min Shipping and Export Documentation: FCL vs LCL and the Papers a Shipment Needs](/blog/2026/05/garment-export-shipping-documentation) START A CONVERSATION ## Ready to source with _confidence?_ Send a brief and we'll reply within 24 hours, with a first sample in 4 to 10 days. 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